I run mobil 1 full synthetic and lets just say i like to let my motor really breathe. I always change my oil at about 3500(still has a gold color to it) like you guys said before they can go longer but i like to always know i have proper lubrication at 5000 rpms. My friend changes his at about 6000-7000 and runs his just as hard. I have 200,000 and he has about 220,000. He consumes oil and I don't, if I was you with conventional oil keep it old school at 3000 and full synthetic i wouldn't let it go farther than 5500